mmsemultitest_dscdma.m

来自「本程序为CDMA系统中基于MMSE的多用户检测技术」· M 代码 · 共 113 行

%gold_seq.m
function goldseq=gold_seq(fbconnection1,fbconnection2)
mseq1=m_sequence(fbconnection1);
mseq2=m_sequence(fbconnection2);
N=2^length(fbconnection1)-1;
for shift_amount=0:N-1
shift_mseq2=[mseq2(shift_amount+1:N) mseq2(1:shift_amount)];
goldseq(shift_amount+1,:)=mod(mseq1+shift_mseq2,2);
end

%m_sequence.m
function mseq=m_sequence(fbconnection)
n=length(fbconnection);
N=2^n-1;
register=[zeros(1,n-1) 1];
mseq(1)=register(n);
for i=2:N
newregister(1)=mod(sum(fbconnection.*register),2);
for j=2:n
newregister(j)=register(j-1);
end
register=newregister;
mseq(i)=register(n);
end

%lmsmmsemud
clc
fbconnection=[0 1 0 0 1]; 
mseq=m_sequence(fbconnection); 
fbconnection1=[0 0 1 0 1];
fbconnection2=[0 1 1 1 1]; 
goldseq=gold_seq(fbconnection1,fbconnection2); 
N=2^length(fbconnection)-1; 
ind1=find(mseq==0);
mseq(ind1)=-1;
ind2=find(goldseq==0);
goldseq(ind2)=-1;

bit_number=10000; 
K=16;
data=zeros(K,bit_number);
for i=1:K
data(i,:)=randsrc(1,bit_number);
end
r=zeros(N,bit_number);
rideal=zeros(N,bit_number);
r1=zeros(N,bit_number);
SNR=-30;
for k=1:K 
r1=goldseq(k,:)'*data(k,:);
rideal=rideal+r1;
r1=awgn(r1,SNR);
r=r+r1;
end

%lms 算法
userk=10;
lmsN=bit_number;
inp=goldseq(1,:)*r;
max_inp=max(inp);
inp=inp/max_inp;
d=data(userk,:);
[dtemp,totallength]=size(d);

lmsN=60;
w=zeros(userk,1);
for n=1:lmsN
u=inp(n)*ones(userk,1);%u=inp(n:-1:n-userk+1);
y(n)=w'*u;%y(n)=u*w;
e(n)=d(n)-y(n);
if n<20
mu=0.32;
else
mu=0.15;
end
w=w+mu*u*e(n);%w=w+mu*u'*e(n);
end
for n=lmsN+1:totallength
u=inp(n)*ones(userk,1); %u=inp(n:-1:n-userk+1);
y(n)=w'*u; % y(n)=u*w;
e(n)=d(n)-y(n);
end

tright=0;
newy=sign(y); %最后输出数据
for lmsi=2:bit_number
if newy(lmsi)==d(lmsi)
tright=1+tright; %与原始数据对比,正确的个数
end
end

trightf=0;
newinp=sign(inp); %非多用户,最后输出数据
for lmsi=2:bit_number
if newinp(lmsi)==d(lmsi)
trightf=1+trightf; %与原始数据对比,正确的个数
end
end

checkr=[newy;d];

hold on
plot(d)
plot(y,'r');
title('System output') ;
xlabel('Samples')
ylabel('True and estimated output')
figure
semilogy((abs(e))) ;
title('Error curve') ;
xlabel('Samples')
ylabel('Error value')